Our Bosch condenser tumble dryer is doing the same. It stinks, so much so we thought we had a gas leak and called the emergancy gas number. Engineers turned up, killed all the electrics and tested the whole house with their sniffers. They agreed that it did smell of gas but couldn't actually detect any. Lots of crawling around later and we found the smell coming from the machine. We stopped using the tumble dryer for the next couple of months (Moving house). We then called Boshe out to investigate the smell this weekend but they could not find fault (tested the tumbler with a wet t-towel. We put a full load in yesterday and smell has come back with a vengeance.
We called Bosch again who say they will charge us if they can't find a fault....
....It stinks
oh and yes we do actually wash the clothes before drying them ;)
Mr. S Rush, July 2009